Golf club designers who want to make a club that is forgiving and easy to hit may turn to a multi-material or cavity-backed construction. Some such designs replace certain areas of the club head, such as the striking face or sole, with a second material that can be either heavier or lighter than the first material. By incorporating additional materials of varying densities or providing cavities and undercuts, mass can be “freed up” and used in perimeter weighting to enhance the moment of inertia. However, due to construction limitations or requirements, some of these designs inadvertently thicken the top portion of the club head.
Where a club head has a body made of a dense material such as metal, thickening the top portion of the club head raises the center of gravity. Unfortunately, this has adverse effects on playability. Some golfers find a club most useful if the center of gravity is low, getting the weight of the club head under the ball.